Intervertebral spinal implant

ABSTRACT

An intervertebral implant for implantation in a treated area of an intervertebral space between vertebral bodies of a spine is provided. The upper surface and the lower surface of the implant each have a contact area capable of engaging with anatomy in the treated area, and the upper and lower surfaces define a through-hole having an inner surface extending through the spacer body. A first and second sidewalls extend from a front end and a back end, wherein the first and second sidewalls are configured with engagement portions positioned in close proximity to the front end and the back end. The front end and the back end are configured with a threaded hole for receiving an instrument for inserting the intervertebral implant into the intervertebral disc space.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 13/292,316, filed Nov. 9, 2011, which is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure generally relates to a fixation device forpositioning and immobilizing at least two adjacent vertebrae. Inparticular, the present invention relates to an interbody fusion devicefor implementation in the spine.

BACKGROUND

The spine is the axis of the skeleton on which all of the body parts“hang”. In humans, the normal spine has seven cervical, twelve thoracicand five lumbar segments. The lumbar spine situs upon the sacrum, whichthen attaches to the pelvis, and in turn is supported by the hip and legbones. The bony vertebral bodies of the spine are separated byintervertebral discs, which act as joints but allow known degrees offlexion, extension, lateral bending, and axial rotation.

The typical vertebra has a thick anterior bone mass called the vertebralbody, with a neural (vertebral) arch that arises from the posteriorsurface of the vertebral body. The central of adjacent vertebrae aresupported by intervertebral discs. The spinal disc and/or vertebralbodies may be displaced or damaged due to trauma, disease, degenerativedefects, or wear over an extended period of time. One result of thisdisplacement or damage to a spinal disc or vertebral body may be chronicback pain. In many cases, to alleviate back pain from degenerated ofherniated discs, the disc is removed along with all or part of at leastone neighboring vertebrae and is replaced by an implant that promotesfusion of the remaining bony anatomy.

However, the success or failure of spinal fusion may depend upon severalfactors. For instance the spacer or implant or cage used to fill thespace left by the removed disc and bony anatomy must be sufficientlystrong to support the spine under a wide range of loading conditions.The spacer should also be configured so that it likely to remain inplace once it has been positioned in the spine by the surgeon.Additionally the material used for the spacer should be biocompatiblematerial and should have a configured that promotes bony ingrowth. Thereis a need for an implant that can be inserted laterally into thevertebral disc space between adjacent vertebrae.

SUMMARY OF THE INVENTION

An intervertebral implant for implantation in a treated area of anintervertebral space between vertebral bodies of a spine is provided.The upper surface and the lower surface of the implant each have acontact area capable of engaging with anatomy in the treated area, andthe upper and lower surfaces define a through-hole having an innersurface extending through the spacer body. A first and second sidewallsextend from a front end and a back end, wherein the first and secondsidewalls are configured with engagement portions positioned in closeproximity to the front end and the back end. The front end and the backend are configured with a threaded hole for receiving an instrument forinserting the intervertebral implant into the intervertebral disc space.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of an intervertebralimplant according to the present invention;

FIG. 2 is a top view of the intervertebral implant;

FIGS. 3 and 4 are side views of the intervertebral implant;

FIGS. 5 and 6 are front and back views of the intervertebral implant;

FIG. 7 is the instrument for engaging with the intervertebral implantduring insertion; and

FIG. 8 is the threaded instrument for engaging with the intervertebralimplant according to the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the disclosure are generally directed to anintervertebral implant for use with the anterior, antero-lateral,lateral, and/or posterior portions of at least one motion segment unitof the spine. The systems of the invention are designed to beconformable to the spinal anatomy, so as to be generally less intrusiveto surrounding tissue and vasculature than existing implants.

Referring now to FIGS. 1-6 one embodiment of a lateral intervertebralimplant is shown. FIG. 1 is a perspective view of the implant accordingto the present invention. FIG. 2 illustrates a top view of the implant10. As illustrated, the implant 10 is substantially rectangular with ahollow interior portion 12. The implant 10 is configured with a taperedfront end 14 and a rectangular back end 16, as shown in FIGS. 3 and 4which illustrate the side views of the implant 10. The implant 10 has anupper surface 18 and a parallel lower surface 20. The two side walls 22and 24 are parallel to one another that extend from the back end 16 tothe front end 14. The side walls 22 and 24 are configured withinstrument attachment portions 26 near the front end 14 and the back end16. The front end 14 and the back end 16 of the implant 10 are providedwith a hole and/or aperture 28 and 30 for receiving an instrument thatis used for inserting the implant 10. The implant 10 is coronally angledand allows for a surgeon to place the implant from the lateral approachregardless of the side of the access or direction of a scoliotic curve.The first side wall may comprise a straight wall and the second sidewall may comprise a curved wall. The second side wall may be a convexwall in relation to the straight wall of the first side wall.

FIGS. 7 and 8 more clearly illustrates the instrument used for insertingthe implant 10 into the intervertebral disc space. The instrument 32comprises a substantially hollow tubular structure 34 having an internalrod 36 which is configured with a turning knob 38 at one end and athreaded portion 40 at the other end for threadeably engaging thethreaded opening of the implant 10. The instrument 32 is configured withtwo extended arms 42 and 44 that engage with the attachment portions 26of the implant. The implant is provided with attachment portions on theside walls of the front end and the back end so that the implant may beinserted in either direction. The internal rod 36 can be threaded intothe back end of the implant or the front end depending on the surgeon'spreference.

Bone graft and other bone material may be packed within the hollowportion of the implant which serves to promote bone ingrowth between theimplant and the adjacent vertebrae. Once the bone ingrowth occurs, theimplant will be a permanent fixture preventing dislodgement of theimplant as well as preventing any movement between the adjacentvertebrae.

The implant 10 is also provided with a plurality of teeth projectionsextending form the upper and lower surfaces of the implant 10. Althoughthe present implant illustrates teeth projections on the upper and lowersurface, any type of projections may be utilized such as ridges. Theseprojections prevent the implant from moving between the vertebrae, thuspreventing movement of the implant prior to fusion.

Referring now to FIGS. 1-8, the method of inserting the implant 10 isdescribed as follows. First, the threaded end of the internal rod of theinstrument 32 is attached to the threaded opening of the implant byturning of the knob. Once the engaging end is in place, the extendedarms 42 and 44 engage with attachment portions on the sidewalls of theimplant. The implant is then placed at the entrance of the disc spacebetween the two adjacent vertebrae. The knob is then tapped sufficientlyhard enough the drive the implant into the disc space. It should benoted that the size of the implant is generally the same size as thedisc space that is being replaced and can be either larger and/orsmaller based on the intervertebral disc being removed.

While it is apparent that the invention disclosed herein is wellcalculated to fulfill the objects stated above, it will be appreciatedthat numerous modifications and embodiments may be devised by thoseskilled in the art.

What is claimed is:
 1. A surgical method comprising: providing aninsertion instrument, wherein the insertion instrument comprises athreaded portion, a first extended arm and a second extended arm,wherein the first extended arm and second extended arm extend aredisposed laterally in relation to the threaded portion; attaching animplant to the insertion instrument, wherein the implant comprises afront end and a back end, wherein the front end includes a frontaperture and the back end includes a back aperture, wherein the threadedportion of the insertion instrument is capable of threading into eitherthe front aperture or back aperture of the implant, wherein the implanthas two side walls that extend from the back end to the front end, saidside walls configured with engagement portions spaced away from saidfront and back ends and configured to receive the extended arms of theinsertion instrument; packing graft material in the implant; anddelivering the implant via the insertion instrument into a disc space.2. The surgical method of claim 1, wherein the implant comprises ahollow interior portion for receiving the graft material.
 3. Thesurgical method of claim 1, wherein the implant comprises a taperedfront end.
 4. The surgical method of claim 1, wherein the implantcomprises a second side wall that extend between the front end and theback end, wherein the first side wall comprises a straight wall and thesecond side wall comprises a curved wall.
 5. The surgical method ofclaim 4, wherein the implant comprises a first pair of lateralinstrument attachment portions positioned near the front end and asecond pair of lateral instrument attachment portions positioned nearthe back end.
 6. The surgical method of claim 1, wherein delivering theimplant comprises inserting the implant into the disc space via alateral approach.
 7. The surgical method of claim 6, wherein the implantcomprises a tapered front end.
 8. The surgical method of claim 6,wherein the implant comprises a hollow interior portion for receivingthe graft material.
 9. The surgical method of claim 6, wherein theimplant comprises a first side wall and a second side wall that extendsbetween the front end and the back end, wherein the first side wallcomprises a straight wall and the second side wall comprises a convexwall in relation to the straight wall.
 10. A surgical method comprising:providing an insertion instrument, wherein the insertion instrumentcomprises a threaded portion, a first extended arm and a second extendedarm, wherein the first extended arm and second extended arm extend aredisposed laterally in relation to the threaded portion; attaching animplant to the insertion instrument by threading the threaded portioninto the implant and gripping the implant between the first extended armand the second extended arm, wherein the implant comprises a front endand a back end, wherein the front end includes a front aperture and theback end includes a back aperture, wherein the threaded portion of theinsertion instrument is capable of threading into either the frontaperture or back aperture of the implant, wherein the implant has twoside walls that extend from the back end to the front end, said sidewalls configured with engagement portions spaced away from said frontand back ends and configured to receive the extended arms of theinsertion instrument; and delivering the implant via the insertioninstrument into a disc space.
 11. The surgical method of claim 10,wherein the implant comprises a hollow interior portion for receivingthe graft material.
 12. The surgical method of claim 10, wherein theimplant comprises a tapered front end.
 13. The surgical method of claim10, wherein the implant comprises a second side wall that extend betweenthe front end and the back end, wherein the first side wall comprises astraight wall and the second side wall comprises a curved wall.
 14. Thesurgical method of claim 13, wherein the implant comprises a first pairof lateral instrument attachment portions positioned near the front endand a second pair of lateral instrument attachment portions positionednear the back end.
 15. The surgical method of claim 10, whereindelivering the implant comprises inserting the implant into the discspace via a lateral approach.
 16. The surgical method of claim 15,wherein the implant comprises a tapered front end.
 17. The surgicalmethod of claim 15, wherein the implant comprises a hollow interiorportion for receiving the graft material.
 18. The surgical method ofclaim 15, wherein the implant comprises a first side wall and a secondside wall that extends between the front end and the back end, whereinthe first side wall comprises a straight wall and the second side wallcomprises a convex wall in relation to the straight wall.